Android Developers Blog

Getting your Android app ready for Autofill

16 November 2017

Posted by Wojtek Kalicinski, Android Developer Advocate, Akshay Kannan, Product Manager for Android Authentication, and Felipe Leme, Software Engineer on Android Frameworks Starting in Oreo, Autofill makes it easy for users to provide credit cards, logins, addresses, and other information to apps. Forms in your apps can now be filled automatically, and your users no longer have to remember complicated passwords or type the same bits of information more than once. Users can choose from multiple Autofill services (similar to keyboards today). By default, we include Autofill with Google, but users can also select any third party Autofill app of their choice. Users can manage this from Settings->System->Languages>Advanced->Autofill service.

What's available today Today, Autofill with Google supports filing credit cards, addresses, logins, names, and phone numbers. When logging in or creating an account for the first time, Autofill also allows users to save the new credentials to their account. If you use WebViews in your app, which many apps do for logins and other screens, your users can now also benefit from Autofill support, as long as they have Chrome 61 or later installed. The Autofill API is open for anyone to implement a service. We are actively working with 1Password, Dashlane, Keeper, and LastPass to help them with their implementations towards becoming certified on Android. We will be certifying password managers and adding them to a curated section in the Play Store, which the "Add service" button in settings will link to. If you are a password manager and would like to be certified, please get in touch. What you need to do as a developer As an app developer, there are a few simple things you can do to take advantage of this new functionality and make sure that it works in your apps: Test your app and annotate your views if needed In many cases, Autofill may work in your app without any effort. But to ensure consistent behavior, we recommend providing explicit hints to tell the framework about the contents of your field. You can do this using either the android:autofillHints attribute or the setAutofillHints() method. Similarly, with WebViews in your apps, you can use HTML Autocomplete Attributes to provide hints about fields. Autofill will work in WebViews as long as you have Chrome 61 or later installed on your device. Even if your app is using custom views, you can also define the metadata that allows autofill to work. For views where Autofill does not make sense, such as a Captcha or a message compose box, you can explicitly mark the view as IMPORTANT_FOR_AUTOFILL_NO (or IMPORTANT_FOR_AUTOFILL_NO_EXCLUDE_DESCENDANTS in the root of a view hierarchy). Use this field responsibly, and remember that users can always bypass this by long pressing an EditText and selecting "Autofill" in the overflow menu. Affiliate your website and mobile app Autofill with Google can seamlessly share logins across websites and mobile apps ‒ passwords saved through Chrome can also be provided to native apps. But in order for this to work, as an app developer, you must explicitly declare the association between your website with your mobile app. This involves 2 steps: Step 1: Host a JSON file at yourdomain.com/.well-known/assetlinks.json If you've used technologies like App Links or Google Smart Lock before, you might have heard about the Digital Asset Links (DAL) file. It's a JSON file placed under a well known location in your website that lets you make public, verifiable statements about other apps or websites. You should follow the Smart Lock for Passwords guide for information about how to create and host the DAL file correctly on your server. Even though Smart Lock is a more advanced way of signing users into your app, our Autofill service uses the same infrastructure to verify app-website associations. What's more, because DAL files are public, third-party Autofill service developers can also use the association information to secure their implementations. Step 2: Update your App's Manifest with the same information Once again, follow the Smart Lock for Passwords guide to do this, under "Declare the association in the Android app." You'll need to update your app's manifest file with an asset_statements resource, which links to the URL where your assetlinks.json file is hosted. Once that's done, you'll need to submit your updated app to the Play Store, and fill out the Affiliation Submission Form for the association to go live. When using Android Studio 3.0, the App Links Assistant can generate all of this for you. When you open the DAL generator tool (Tools -> App Links Assistant -> Open Digital Asset Links File Generator), simply make sure you enable the new checkbox labeled "Support sharing credentials between the app and website".

Then, click on "Generate Digital Asset Links file", and copy the preview content to the DAL file hosted on your server and in your app. Please remember to verify that the selected domain names and certificates are correct. Future work It's still very early days for Autofill in Android. We are continuing to make some major investments going forward to improve the experience, whether you use Autofill with Google or a third party password manager. Some of our key areas of investment include:

Autofill with Google: We want to provide a great experience out of the box, so we include Autofill with Google with all Oreo devices. We're constantly improving our field detection and data quality, as well as expanding our support for saving more types of data.

WebView support: We introduced initial support for filling WebViews in Chrome 61, and we'll be continuing to test, harden, and make improvements to this integration over time, so if your app uses WebViews you'll still be able to benefit from this functionality.

Third party app support: We are working with the ecosystem to make sure that apps work as intended with the Autofill framework. We urge you as developers to give your app a spin on Android Oreo and make sure that things work as expected with Autofill enabled. For more info, see our full documentation on the Autofill Framework.

If you encounter any issues or have any suggestions for how we can make this better for you, please send us feedback. .blgimg1 img { width: 40%; border: 0; margin: 0; padding: 10px 0 0px 0; } .blgimg2 img { width: 100%; border: 0; margin: 0; padding: 10px 0 0px 0; }

How the Pixel 2’s security module delivers enterprise-grade security

13 November 2017

Posted by Xiaowen Xin, Android Security Team The new Google Pixel 2 ships with a dedicated hardware security module designed to be robust against physical attacks. This hardware module performs lockscreen passcode verification and protects your lock screen better than software alone. To learn more about the new protections, let's first review the role of the lock screen. Enabling a lock screen protects your data, not just against casual thieves, but also against sophisticated attacks. Many Android devices, including all Pixel phones, use your lockscreen passcode to derive the key that is then used to encrypt your data. Before you unlock your phone for the first time after a reboot, an attacker cannot recover the key (and hence your data) without knowing your passcode first. To protect against brute-force guessing your passcode, devices running Android 7.0+ verify your attempts in a secure environment that limits how often you can repeatedly guess. Only when the secure environment has successfully verified your passcode does it reveal a device and user-specific secret used to derive the disk encryption key. Benefits of tamper-resistant hardware The goal of these protections is to prevent attackers from decrypting your data without knowing your passcode, but the protections are only as strong as the secure environment that verifies the passcode. Performing these types of security-critical operations in tamper-resistant hardware significantly increases the difficulty of attacking it.

Tamper-resistant hardware comes in the form of a discrete chip separate from the System on a Chip (SoC). It includes its own flash, RAM, and other resources inside a single package, so it can fully control its own execution. It can also detect and defend against outside attempts to physically tamper with it. In particular:

Because it has its own dedicated RAM, it's robust against many side-channel information leakage attacks, such as those described in the TruSpy cache side-channel paper.

Because it has its own dedicated flash, it's harder to interfere with its ability to store state persistently.

It loads its operating system and software directly from internal ROM and flash, and it controls all updates to it, so attackers can't directly tamper with its software to inject malicious code.

Tamper-resistant hardware is resilient against many physical fault injection techniques including attempts to run outside normal operating conditions, such as wrong voltage, wrong clock speed, or wrong temperature. This is standardized in specifications such as the SmartCard IC Platform Protection Profile, and tamper-resistant hardware is often certified to these standards.

Tamper-resistant hardware is usually housed in a package that is resistant to physical penetration and designed to resist side channel attacks, including power analysis, timing analysis, and electromagnetic sniffing, such as described in the SoC it to EM paper.

Security module in Pixel 2 The new Google Pixel 2 ships with a security module built using tamper-resistant hardware that protects your lock screen and your data against many sophisticated hardware attacks. In addition to all the benefits already mentioned, the security module in Pixel 2 also helps protect you against software-only attacks:

Because it performs very few functions, it has a super small attack surface.

With passcode verification happening in the security module, even in the event of a full compromise elsewhere, the attacker cannot derive your disk encryption key without compromising the security module first.

The security module is designed so that nobody, including Google, can update the passcode verification logic to a weakened version without knowing your passcode first.

Summary Just like many other Google products, such as Chromebooks and Cloud, Android and Pixel are investing in additional hardware protections to make your device more secure. With the new Google Pixel 2, your data is safer against an entire class of sophisticated hardware attacks. .blogimg1 img { width: 100%; border: 0; margin: 0; padding: 10px 0 0px 0; }

10 things you might be doing wrong when using the SafetyNet Attestation API

13 November 2017

Posted by Oscar Rodriguez, Developer Advocate The SafetyNet Attestation API helps you assess the security and compatibility of the Android environments in which your apps run. Since it was introduced in March 2015, many developers have successfully integrated it into their Android apps to make more informed decisions based on the integrity and compatibility of the devices running their apps. Throughout the years, the SafetyNet Attestation API has evolved, and its adoption has steadily increased. However, as with any security/anti-abuse related API, there are many common pitfalls that may lead developers into developing unstable systems, or worse, into a false sense of security. In this post, we provide a list of the most common mistakes we have seen developers make when integrating the SafetyNet Attestation API. 1. Not getting an API key Just like many other Google APIs, the SafetyNet Attestation API requires an API key in order to run. Furthermore, the SafetyNet Attestation API has a per-key usage quota. Although you can get this quota increased, you need to provide your API key to do so. Getting an API key is easy and free of charge. There is no reason not to get an API key, so if you haven't already, get an API key now. 2. Not using the latest version of the API The SafetyNet Attestation API has evolved throughout its history, and with it, there have been some interface changes. Most recently, with the release of Google Play services 11.0.0, we revamped the entire SafetyNet API to offer an interface that is easier and more streamlined to use: the new API uses SafetyNetClient instead of SafetyNetApi, which is now deprecated, so make sure you update your implementation to use the latest version of the API. Most devices should have the latest version of Google Play services installed, but if a device doesn't have Google Play services installed, or doesn't have it up to date, using the SafetyNet Attestation API may lead to the app becoming unresponsive or crashing. You can prevent this by checking the installed version of Google Play services before using the API. 3. Using nonces incorrectly The SafetyNet Attestation API lets you set a nonce to uniquely and globally identify each call to the API. Use this feature to prevent a malicious user from reusing a successful attestation result in place of an unsuccessful result (also known as a Replay Attack). One good way to create a nonce is to create a large (16 bytes or longer) random number on your server using a cryptographically-secure random function. The SafetyNet attestation response includes the nonce you set, so make sure you verify that the returned nonce matches the one you included in the request you made. 4. Not checking the results on your server SafetyNet can provide useful signals about the state of the device in which your app is running. However, if the logic that acts on these signals is only implemented and enforced directly on the device, an attacker could be able to modify your app and bypass any checks you perform. To prevent this situation, you should run any logic that verifies the attestation result and enforces any actions based on them on a server that you control and trust. 5. Using the test attestation verification service for production In order to simplify development and testing of the SafetyNet Attestation API, Google offers an online verification service that checks the digital signature of a SafetyNet Attestation result using a simple HTTPS request. As useful as this service may seem, it is designed for test purposes only, and it has very strict usage quotas that will not be increased upon request. Instead, you should implement the digital signature verification logic on your server in a way that it doesn't depend on Google's servers. Most JWT libraries offer signature verification functionality, and we have code samples that show how to perform this verification in Java and C#. We plan to provide samples for more languages in the future. 6. Not checking the nonce, timestamp, APK name, and hashes The SafetyNet Attestation API is most widely known for its integrity and compatibility checks, whose results are returned in ctsProfileMatch and basicIntegrity. Although these two values are indeed very useful, you should check the other values in the response, as they contain important information as well. Use nonce to match a response to its request, as explained above, and use timestampMs to check how much time has passed since you made the request and you got the response. A delayed response that arrives several hours or days after the request may suggest suspicious activity. Use apkPackageName to check the name of the APK that made the attestation request, and match apkDigestSha256 and apkCertificateDigestSha256 to those from your app's signed APK in Google Play, to get a signal about the integrity of the installed app. Remember that the trustworthiness of the response as a whole is tied to the results of ctsProfileMatch and basicIntegrity. It is not unthinkable for a compromised device that fails basicIntegrity to have forged the rest of the values in the response. 7. Not understanding the differences between ctsProfileMatch and basicIntegrity The SafetyNet Attestation API initially provided a single value called basicIntegrity to help developers determine the integrity of a device. As the API evolved, we introduced a new, stricter check whose results appear in a value called ctsProfileMatch, which allows developers to more finely evaluate the devices on which their app is running. In broad terms, basicIntegrity gives you a signal about the general integrity of the device and its API. Rooted devices fail basicIntegrity, as do emulators, virtual devices, and devices with signs of tampering, such as API hooks. On the other hand, ctsProfileMatch gives you a much stricter signal about the compatibility of the device. Only unmodified devices that have been certified by Google can pass ctsProfileMatch. Devices that will fail ctsProfileMatch include the following:

Devices that fail basicIntegrity

Devices with an unlocked bootloader

Devices with a custom system image (custom ROM)

Devices for which the manufactured didn't apply for, or pass, Google certification

Devices with a system image built directly from the Android Open Source Program source files

Devices with a system image distributed as part of a beta or developer preview program (including the Android Beta Program)

8. Not having a strategy for timing attestation checks The SafetyNet Attestation API gives you a snapshot of the state of a device at the moment when the attestation request was made. A successful attestation doesn't necessarily mean that the device would have passed attestation in the past, or that it will in the future. Because an attestation is just a spot check, you should plan a sensible strategy for choosing when to make attestation requests. You may choose to require successful attestations before users make in-app purchases, after a certain number of days have passed since the last successful attestation, each time your app is launched, after every reboot, or any other strategy that makes sense for your app. Keep in mind that an attestation request is computationally expensive, consumes battery and bandwidth, and uses your quota. We recommend you plan a strategy to use the least amount of attestations required to satisfy your use case. 9. Using the SafetyNet Attestation API results as the only signal to attack abuse It may be tempting to think that the SafetyNet Attestation API provides all the necessary signals for protecting an app against abusers, and use it as the only signal for building an anti-abuse system. The SafetyNet Attestation API can only give signals about the state of a device, not the intent of a user, which is what an anti-abuse system should be designed to detect. Therefore, you might want to consider including other signals, such as access logs and behavioral patterns, to more accurately detect abusive users, and consider not blocking users solely on a failed attestation. Furthermore, there are many other conditions that cause an attestation to fail, such as network connection problems, quota issues, and other transient problems. In other words, not all users who fail attestation are necessarily abusers, and not all abusers will necessarily fail attestation. By blocking users solely on their attestation results, you might be missing abusive users that don't fail attestations. Furthermore, you might also be blocking legitimate, loyal customers who fail attestations for reasons other than abuse. 10. Not monitoring and managing your usage quota As mentioned before, the SafetyNet Attestation API is rate limited, and there is a default quota of 10,000 requests per day for each API key. Although this quota might be enough for most development, testing, and initial app launches, your app might reach the default limit as it increases in popularity. To prevent inadvertently reaching your quota and getting attestation errors, you should build a system that monitors your usage of the API and warns you well before you reach your quota so you can get it increased. You should also be prepared to handle attestation failures because of an exceeded quota and avoid blocking all your users in this situation. If you are close to reaching your quota, or expect a short-term spike that may lead you to exceed your quota, you can submit this form to request short or long-term increases to the quota for your API key. This process, as well as the additional quota, is free of charge.

Making Pixel better for Drivers

09 November 2017

Posted by Marc Stogaitis and Tajinder Gadh, Software Engineers

Driving is an essential part of our daily activities. So at Google we spend a lot of time thinking how we can make Android devices better and safer for our users. How we can prevent distracted driving and together build an open ecosystem to enable safety first smartphone experiences.
Recently we launched Driving Do-Not-Disturb on the newly announced Pixel 2 generation of devices. Once enabled, Driving Do-Not-Disturb automatically puts your device into a do not disturb mode while driving. During this mode any incoming messages and notifications are silenced while you can still receive incoming calls, navigation directions and voice interactions using a connected Car bluetooth. The product is designed to limit distractions during driving while at the same time not getting in the way so users can continue to use navigation or other similar apps with minimal friction.
Behind the scenes, it uses AI powered on-device Activity Recognition that detects when a person is driving using low power signals from multiple sensors, bluetooth and WiFi. Activity Recognition uses the Android Sensor Hub to ensure low latency, low power and accurate driving detection.
This is a next step in our journey, but we are far from done. Early next year we are introducing the Activity Recognition Transition API, which is the same API used by Driving Do Not Disturb to build distraction-free driving experiences.
We appreciate the feedback, and will continue to listen to your feedback as the product evolves.
If you have questions about setting up the Driving Do-Not-Disturb, check out our Help Center.

Google and Ideas United announce Infinite Deviation: Games winners

07 November 2017

Posted by Kate Brennan and Mathilde Cohen Solal, Google Play and Daraiha Greene, CS in Media Google Play is committed to empowering new and existing voices in gaming. Earlier this year, we hosted the Indie Games Festival and sponsored the Girls Make Games summer camp. We also announced a collaboration between Infinite Deviation and Google Play. Infinite Deviation is an initiative created by Google Computer Science (CS) in Media and Ideas United in order to tackle issues of representation in computer science. The collaboration between Google Play and Ideas United brought the Infinite Deviation program to gaming, called Infinite Deviation: Games. The program invited game designers from all backgrounds to pitch an original mobile game concept that resonates with underrepresented audiences. Today we are excited to announce the three teams selected for the Infinite Deviation: Games development program. A select panel of industry experts reviewed applications and chose the top three ideas. The judging panel included Colleen Macklin (Founder and Co-Director, PETLab), Jeremy Vanhoozer (Senior Creative Director, Plants vs Zombies), Molly Proffitt (CEO, Ker-Chunk Games), Shirin Laor-Raz Salemnia (Founder and CEO, PlayWerks), and Sarah Thomson (Global BD Lead, Indies, Google). These judges scored and delivered personal feedback for each submission, with the three highest scoring games moving into further development. Here's a closer look at the three games we'll be funding and supporting development over the next six months: Historic Gay Bar Tycoon Mo Cohen & Maria Del Castillo Infantas - Queermo Games Historic Gay Bar Tycoon (name pending) starts you off with a brand new queer bar in the 1920s. This game explores the role bars played in LGBT history. Will your bar survive revolutions, epidemics, and the rise of dating apps?

Queermo Games is pretty much what it sounds like: a scrappy and small indie game developing team just trying to make more LGBT games. Conveniently, they are also next door neighbors. Maria is a queer Latina who handles the art and the music, and Mo is a non-binary Jewish queer who tackles the programming and writing. Together, they also work on another longer-term project called Queer Quest with their buddy Hagen. Burn Ban Harrison Barton & Morgan Rowe - Pride Interactive Burn Ban is an interactive visual novel in which you assume the role of Twig, a mentally ill queer girl. After showing destructive tendencies to cope with the death of a close friend, she is sent to Camp Sisquoc, a summer retreat for misguided students. After attending the camp for a few days, her dead friend's online social media page mysteriously starts posting again, and Twig and friends are set with determining the mystery behind the posts.

Pride Interactive is currently made up of two developers, Harrison Barton and Morgan Rowe. Pride Interactive was started as a student game team, and is now continuing on to develop independent projects. Pride Interactive endeavors to further their mission of creating a more diverse environment in the industry through games that deal with serious themes, and diverse character driven narratives. Ghost in the Graveyard Adnan Agha, Vivian Allum, and Armand Silvani - Ghost Stories Ghost in the Graveyard is a story-driven mobile mystery game where you snoop through your missing brother's old phone to try and find him. "Can you find a missing person when all you have is their phone?"

Ghost Stories is a three member team from NYC with a mission to create genuine and unique experiences that connect with players. The team consists of Vivian, the lead designer and programmer, Armand, the artist and writer, and Adnan, the programmer and resident ghost. They've previously published a school project to the Xbox One and are thrilled to be able to work with Infinite Deviation to publish to Google Play. You can find more information about the program at InfiniteDeviation.com/Games. Congratulations to the three winners and thanks to all the people who have entered the competition for their continuous work to push the boundaries of gaming design and providing a unique voice to the industry. .blgimg1 img { width: 50%; border: 0; margin: 0; padding: 10px 0 0px 0; } .blgimg2 img { width: 50%; border: 0; margin: 0; padding: 10px 0 10px 0; } .blgimg3 img { width: 50%; border: 0; margin: 0; padding: 20px 0 10px 0; } .blgimg4 img { width: 50%; border: 0; margin: 0; padding: 20px 0 10px 0; }

Announcing Architecture Components 1.0 Stable

06 November 2017

Posted by Lukas Bergstrom, Product Manager, Android Developer Frameworks Team

Android runs on billions of devices, from high-end phones to airplane seatbacks. The Android OS manages resources aggressively to perform well on this huge range of devices, and sometimes that can make building robust apps complicated. To make it easier, we launched a preview of Architecture Components at Google I/O to provide guidance on app architecture, with libraries for common tasks like lifecycle management and data persistence. Together, these foundational components make it possible to write modular apps with less boilerplate code, so developers can focus on innovating instead of reinventing the wheel - and we hope to keep building on this foundation in the future. Today we're happy to announce that the Room and Lifecycle Architecture Components libraries have reached 1.0 stable. These APIs are ready for production apps and libraries, and are our recommendation for developers looking for help with app architecture and local storage (although they're only recommended, not required.) Lifecycles are now also integrated with the Support Library, so you can use them with standard classes like AppCompatActivity. Although we're declaring them stable today, the beta components are already used in apps that together, have billions of installs. Top developers, like Zappos, have been able to spend more time on what's important thanks to Architecture Components:

Prior to the release of Android Architecture Components we had our own ViewModel implementation. We used Loaders and Dependency Injection to persist our ViewModel through config changes. We recently switched to the Architecture Components ViewModel implementation and all that boilerplate went away. We found that we were able to spend more time on design, business logic and testing, and less on writing boilerplate or worrying about Android lifecycle issues.

We've also started to use LiveData which hooks directly into the Activity lifecycle. We use it to retrieve and display network data and no longer have to concern ourselves with network call subscription management.

- David Henry, Android Software Engineer, Zappos

Architecture Components provide a simple, flexible and practical approach that frees developers from some common problems so they can focus on building great experiences. This is based on core building blocks tied together by guidance on app architecture. LifecyclesEvery Android developer has to deal with the operating system starting, stopping and destroying their Activities. That means managing the state of components - such as observables used to update UI - as you move through the lifecycle. Lifecycles enables the creation of lifecycle-aware components that manage their own lifecycles, reducing the possibility of leaks or crashes. The Lifecycle library is the foundation for other Architecture Components like LiveData. LiveDataLiveData is a lifecycle-aware observable that holds data and provides updates. Your UI code subscribes to changes and provides LiveData a reference to its Lifecycle. Because LiveData is lifecycle-aware, it provides updates when its Lifecycle is started or resumed, but stops providing updates when the LifecycleOwner is destroyed. LiveData is a simple way to build reactive UIs that are safer and more performant. ViewModelViewModel separates ownership of view data and logic from lifecycle-bound entities like Activities and Fragments. A ViewModel is retained until its associated Activity or Fragment is disposed of forever - that means view data survives events like a Fragment being recreated due to rotation. ViewModels not only eliminate common lifecycle issues, they help build UIs that are more modular and easier to test. RoomNearly all apps need to store data locally. While Android has bundled SQLite with the platform since version 1, using it directly can be painful. Room is a simple object-mapping layer that provides the full power of SQlite with less boilerplate. Features like compile-time query verification and built-in migration make it easier to build a robust persistence layer, while integration with LiveData lets Room provide database-backed, lifecycle-aware observables. Room blends of simplicity, power and robustness for managing local storage, and we hope you give it a try. Guide to App Architecture and moreLast but not least, we created a Guide to App Architecture that provides core principles applicable to all developers, and specific guidance on using Architecture Components together. Because we've heard from you that clear and consistent guidance is important, today we're updating developer documentation to point to Architecture Components where appropriate. We also have a rich set of videos, codelabs and sample apps available at the Architecture Components site, with more to come. Watch this spaceAlthough the first set of Architecture Components is now stable, we know there's more work to do. Over the last few months, we've listened to your feedback and made improvements. We also recently launched a new Architecture Component, PagedList, to alpha, in response to your feedback that handling large datasets with RecyclerView is too difficult. This is just the beginning - we have more major components under development that we're looking to announce in the upcoming months. Our hope with Architecture Components is to free developers to focus on providing unique new experiences for mobile devices. We're glad we can finally announce them as stable for production use. We'd like to thank the community, which has given such great feedback along the way, and we look forward to continuing the discussion in the comments of this post. Finally, for those of you who've been waiting for this stable launch, get started today. .blogcap { font-style:italic; margin:1.5em 2em 1.5em 2em; } .blogimg1 img { width:25%; border:0; margin:0; padding:; } .imgfloat img { float:right; width: 42%; margin: 0; padding:2em; border: 0; padding: 10px 0 10px 0; }

Update on Kotlin for Android

02 November 2017

Posted by James Lau, Product Manager (twitter.com/jmslau) Today is the beginning of KotlinConf. It's been almost 6 months since we announced Kotlin as a first-class language for Android at Google I/O. During this period, the number of apps on Google Play using Kotlin has more than doubled. More than 17% of the projects in Android Studio 3.0 are now using Kotlin. We are really excited about the strong momentum, and we are thrilled that Android developers all over the world are discovering the joy of Kotlin programming. Kotlin for Android is production-ready. From startups to Fortune 500 companies, developers are already using Kotlin to build their apps. Developers from Pinterest, to Expedia, to Basecamp -- and many others -- are finding their use of Kotlin is increasing productivity and their overall developer happiness levels. Take a look at some of their experiences with Kotlin below. With the recent release of Android Studio 3.0, there is now a stable version of our IDE that has Kotlin support built-in. With Support Library 27, we have started adding nullability annotations to make the APIs friendlier to use in Kotlin. We recently published the Android Kotlin Guides on GitHub to provide some guidance for Android Kotlin style and interop. We have also been porting some of our Android samples to Kotlin, and we are adding Kotlin to our official documentation. Android Studio 3.0 Last week, we released Android Studio 3.0 on the stable channel. This is the first stable release of Android Studio that has Kotlin support built-in. Building on the strength of IntelliJ's Kotlin support, many critical IDE features like code completion and syntax highlighting work well for Kotlin. You can choose to convert Java code to Kotlin by using Code → Convert Java File to Kotlin File, or you can convert snippets of code just by pasting Java code into a Kotlin file. Project and code templates have also been updated with Kotlin support. When you create a new project or add a new code file, you can choose Kotlin as one of the language options. The tooling experience with Kotlin is by no means perfect yet. We are aware of several known issues, and we will continue to improve the IDE support for Kotlin in future releases. Android Kotlin Guides There are two separate Android Kotlin Guides:

Style guide - details a set of rules and coding standards that Google recommends when writing Kotlin for Android. The guide addresses naming conventions, formatting, structure of the source contents, and much more.

Interop guide - provides a set of rules for creating APIs in the Java and Kotlin programming languages, so that the consuming code in the other language will feel idiomatic.

We intend these guides to be living documents and will evolve them over time. They are hosted on GitHub and we welcome your contributions. Nullability Annotations Null-safety is an important feature of the Kotlin language. It helps developers avoid NullPointerExceptions and improves the quality of their apps. Null-safety is a bit more complicated when using Java code from Kotlin. Since any reference in Java may be null, Kotlin's requirement for strict null-safety becomes impractical for Java objects. Types declared in Java that do not contain nullability annotations are called platform types - this means the Kotlin compiler does not know whether it is nullable or not. When calling methods with variables of platform types, the Kotlin compiler relaxes null-safety checks. That means the overall null-safety of your app is weakened. To let developers take more advantage of Kotlin's strict null-safety, we have started adding nullability annotations in Support Library 27. The Support Library contains a huge API surface area, and we will continue to expand the nullability annotation coverage in the next several releases. In addition, we will also be adding nullability annotations to other Android APIs over time. While the Kotlin adoption growth is fantastic, our commitment to the Java and C++ programming languages remains unchanged. We've added Java 8 language features support in Android Studio 3.0, and we've added more Java 8 language APIs in Android Oreo. We are also continuing to improve our support for C++17 in the NDK. So even if you are not using Kotlin, your language support will continue to improve. It's an exciting time to be an Android developer. If you haven't had a chance to try Kotlin, you can get started by learning the basic syntax and by playing with the excellent Kotlin Koans. When you are ready to use Kotlin in your Android app, you can jump to the Android Kotlin page for more resources. With Kotlin's Java interoperability and Android Studio's Java to Kotlin converter, it's easy to start using Kotlin in your project. Happy Kotlin-ing!

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